Jam resistance performance of UWB BPM impulse radio with time hopping vs. direct sequence

The jam resistance performance of UWB impulse radio with bipolar modulation and time hopping or direct sequence is analyzed in terms of the processing gain theoretically, where the jam interference is modeled as a continuous wide sense stationary random process whose bandwidth is much smaller than the impulse radio bandwidth. The general closed form expressions for the processing gain are derived, and they show when the data rate is fixed, the processing gain can be increased through decreasing the UWB pulse spectrum in the band where the jam interference lies. In particular the condition is presented to judge which spread spectrum technique can provide the superior processing gain, and a signal parameter design guide is given to improve the processing gain of time hopping impulse radio to be a prescribed extent above that of direct sequence impulse radio. Simulations demonstrate the theoretical analysis.